Electrical switch



Jan. 22, 1929.:

' 1,699,514 ALDENDORFF ELEQTRICAL swncn Filed Aug. 26., 19244 l '7 Sheets-Shee 1 Jan. 22, 1929. 1,699,514

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Jan. z2, 1929. r 1,699,514

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F. ALDENDORFF ELECTRICAL SWITCH Jan, 2z, 1929. 1,699,514

Filed Aug.26. 1924 7 Sheets-Sheet 7 Izzvenior fr; @lf-ff wf Patented Jan. 22, 1929.

UNITED STATES 1,699,514 PATENT OFFICE.

FRITZ ALDENDORFF, OF BERLIN-WILMERSDORF, GERMANY; CHARLOTTE ALBEN- DORFF HEIRESS OF SAID FRITZ ALDENDORFE, DECEASED.

ELECTRICAL SWITCH.

Application filed August 26, 1924, Serial No. 734,290, and in Germany September '12, 1923.

This invention relates to an arrangement for setting shafts particularl7 forxelectrical switches and more particularly for electromechanical telephone systems. l

The arrangement according to the invention comprises two co-axial shaft members adapted to be always turned in one and the same direction and one of which is normally held against rotary movement by an electro,- magnetically operated shaft stepping pawl, whilst the other is normally held against rotation by the armature of an electro-magnet. The one shaft member may have a stepping wheel fixed thereto which is normally held against rotation by the stepping pawl and the other shaft `may be hollow and journalled upon the first-shaft member and fixed to a notched member which is held against rotation by the said armature, One of the shaft members may carry a. coupling member adapted to couple the two shaft'members together when one shaft (or the shaft ,mem5 bers) 1s, or are, turned through any desired angle. The notched member fixed to the hollow shaft may be made in the form of a spider that is held against rotation by an electromagneticl armature engaging with a leg of t-he spider. The coupling member carried by the other shaft member may be adapted to also engage with a leg or legs of the spider and to thus couple the shaft members together. The arrangement for setting shafts in accordance with one feature of the invention may consist of two co-axial shafts one within the other, a

' wheel or notched disc fixed to each shaft and a. coupling member for coupling the shafts together which is pivoted on one wheel or disc so that its free end engages with the other wheel or disc when the shafts are coupled together. The coupling member may be in the form of a pivoted electro-mechanically controlled armature shaped at its free end in the form of a rigid member that enters a notc-h in the. notched member fixed to the other shaft when the armature is released by its electromagnet. The rigid member that enters a notch has the formfof a tongue whose lateral edge (or edges) projects further out than its middle part so that, in a coupling operation, a lateral projecting edge may enter into the notch before its-sides register with the` sides of the tongue. An electrical brush or brushes may be carried on by one of the shaft members and 'fixed contacts may be provided which are wiped overby the brush, the said electro-magnet being energized by currents sent through the wiper and the brush or through a contact which is closed whenever the brush carrier reaches a certain position with respect to the contact bank of a switch in which the arrangement for setting shafts is used. The rigid coupling member may normally couple the two shaft members together and be caused to unc'ouple them when current 1s 'sent through the magnet that controls the said coupling member. The two coaxial shaft members may be interconnected by a spiral spring which, when wound up by rotation of the one shaft member applies a torque to the other shaft member. This feature of invention is, in itself, old but forms a part of a novel and useful combination in connection with arrangements or switches in accordance with the present invention.

Another feature of the invention consists in a switch with a wiper.' arranged to move over bank contacts and provided with arrangements for stopping the wiper at a certain point, which arrangements comprise a stopping magnet operated by a current whose duration of flow or interruption is determined by the speed of the wiper and by the number of bank contacts brought into the electrical condition for actuating the stopping magnet. A high speed electric switch is thus obtained with Wipers adapted to be stopped at any desired position, in which the wiper stopping magnet is actuated by placing a certain potential on any desired set of magnet-affecting bank contacts swept over by a wiper in a wiper stopping circuit, the said potential being applied to as many bank contacts as lare necessary to make the time lof travel of the wiper over effective magnetaffecting contacts equal to the time of re- 9 sponse of the said magnet. Switches arranged in the aforcdescribed manner may be used as line finders, group selectors or connectors in electro-mechanical telephone systems( ln such systems the coupling magnet of a group selector or connector has nu- 'merical impulses sent through it from the contacts of an impulse relay controlled by subscribers dialling impulses. The impulses from the contacts of the impulse relay may be sent through bank contacts of the selector or through a contact which is operated whenever the brush carrier reaches a certain position with respect to the contact bank.

In accordancel with another feature of my for affecting xthe electro-magnet in such -a way that the detent is always caused to stop the brushes whenever they have been driven a certain distance. The brush carrying niember may be driven by a' continuously acting force such as a spring. The switch in accordance with this feature of invention may be provided with brush stopping members that cooperate with an electricallyactuating detent that moves into the) path of the brush stopping member in response to current impulses whose circuit depends on the position of the brush carrier. A contact in the circuit of the detent actuating magnet may be operated by apart attached to the brush carrier. Anotherfeature of the invention consists of'a method of wiring the contacts of contact banks of groups of selectors with 50 or more brush ositions. p

The invention is shown in the drawing in which Fig. 1 is a perspective View of a selector for electro-mechanical telephoneexchanges Ain which the arrangement for setting shafts in accordance with the invention is used.

Fig.l2 is a side view of the ,selector shown in Fig. 1,

, Fig. 3 is a more or less diagrammatic perspective' view of the shaft setting arrangement and of the coupling members for cou- 'l'm'g the shaft sections and of the members or setting them in operation.

Fig. 4 is a section through, the shaft sections one of which carries a set of wipers or brushes,

Fig. 5 is a perspective view of a stepping wheel which is fixed to one of' the shaft scctions ,and to which the coupling member, in the form of an electro-magnet armature, is pvoted. .,Fig. 6 shows fragments of bank contact levels of which the, contact bank of a switch :is built up.

Fig. 7 is a perspective view of the wiring of a group of conta-ct banks belonging to three different switches.

Fig. 8 shows the circuits of a line finder and a group selector in accordance with Figs.

Fig. 9 illustrates the circuits of a connector constructed in accordance with Figs. 1-6.

Figs. 10 and 11 shows circuits by which the speed at which the wipers of aA switch according to Figs. 1-3 are driven may be still further increased.

Figs. 12-115 show atnoditied form of switch in which only two' magnets insteadof three are employed. This switch may be used as a group selector or connector or as a linepinder if a contact bank of the speed shown-in Figs. 1 and 3 is employed.

Figs. I16 and 17 show a method of building up contact banks and a manner of-shaping'the soldering tabs of the bank 'contacts' shafts and more particularly switch Journalled inthe hollow core5 is a shaftsection 1 which rests upon a ball 7. The bottom surface of the shaft 1 which abuts upon the ball 7 and the top surface of the screw 6 is tempered to prevent cavities being formed lby the friction of the ball 7.l Fixed to the shaft 1 is a disc 8 and a stepping wheel 9. J ournalled on theshaft 1 is a. hollow shaft or slip 2 with which a notched disc or spider 10 is fixed. The hollow shaft "2. together with the spider 10 carries brushes 11, of which only one is more or less diagrammatical ly 'shown in Fig. 3. VAt the top of the shaft 1 there is a spring box 12 vwhich contains a spring 13 whose one end is fixed to the periphery of the spring box 12 whereby it isunyieldingly attached to the shaft 1, while its second end is fixed to the hollow shaft 2. When thev shaft 1 lis turned in the direction of the arrow 22 the spring 13 is wound up so as to produce a torque which acts upon the hollow shaft 2 so as to tend to move the latter also in the direcion tion of the arrow. The hollow shaft, hown ever, is normally prevented from turning by the armature 14 of the magnet 15, which engages with a leg 16 of the spider 10. The shaft 1 isn'ormally prevented from turning by a stepping pawl 17 engaging with a tooth of the wheel y9, the pawl 17 abutting upon a stop or stroke limiting member 20 which pre vents the pawl 17 frombeing deflected beyond a certain point in the direction of the arrow 21. The rotation of tliestepping wheel 9 in the direction opposite to that of the arrow 22 is prevented by a detent 19. The spring 13 is wound up by sending current impulses through the magnet 18. When the magnet 18 is excited in this manner its arma'- ture 23 together with the lever 24and Ithe stepping pawl 17 attached thereto oscillates so that, at each attraction of the armature 23, the pawl engages with another tooth of the wheel 9 and at each detraction a spring 25 pulls the lever with the stepping pawl 17 forward so that the pawl rotates the disc 9 the distance of o-ne tooth in the direction of the larrow 21. During the rotation ofthe wheel 9 and of the shaft 1 fixed to this the spring 13 is wound up because its inner end is connected to the hollow shaft 2 which is held stationary by the leg 16 and the armature 14 engaging therewith. v' j Pivotally mounted on the stepping wheel 9 is an armature 27 of the magnet 4. By a spring 50 the free end or coupling member 28 of the armature is normally pressed upwards so that the coupling member 28 lies between two legs 16, 162 of the spider and thus couples the shaft l with the hollow shaft 2.

It will now be assumed' that the brush 11 is to be turned through a certain angle, for eX` ample, to Vsuch an extent as will result in the brush 11 coming to a stand-still on the contact 26'. To this end the magnets 4 and 15 are both' energized which results in the coupling member 18 being pulled out from between the legs 16', 162 and in the armature 14' being disengaged from the leg 16 of the spider 10. The spring 13 can now rotate the hollow shaft 2 in the direction of the arrow. This rotation continues only as long as the coupling magnet 4 is kept energized and this energization is effective by a current which flows through the magnet 4, brush 11 and contacts like 29. As soon as the brush 1l reaches a dead contact, say for example contact30, the current flowing through the magnet 14 and the brush 11 is interrupted so that the magnet releases the couplngmember 28. This latter flies upward and rst wipes against the leg of the spider which happens to be passing the member 28 at that moment. As soon as this leg has slipped past the projection 31 of the member 28 this latter is pushed' therefore up by its spring so that the right hand edge of the projection 31 gets into the path of the next spider leg. When this next leg strikes against the side of the projection 21 the member 28 is pushed up still further by its spring so that the left' or Iopposite edge of the member 28 moves up into engagement with the leg 161 withl which it registers. The upward movement of the member 28 between two adjacent legs requires a certain time Vand this time is gained by making the dead contact, for example 30, over which the brush 11 wipes, of such length that sufficient time is gained, for the described coupling action. lVhen the coupling operation is completed the brush 11 will rest upon a contact like 26 between two long' contacts like 30 and 33.

Therotation of the hollow shaft with the brush 11 in the described manner results in the'spring 13 being detensioned or running down to a certain extent. The .spring 13 is rewound by energizing the magnetl so that its armature reengages with a legrof the spider 10, in energizing the magnet 4 so as to. withdraw the coupling member 28 from lthe spider and 'in simultaneously sending current impulses throughthe stepping magnet 18 in order to rotate the stepping wheel with the shaft 1 and the spring box 12 in the direction `of the 'arrow 22. When the stepping wheel 9 has been rotated sutliciently to completely rewind thespring 13 the magnet 18 is deenergized by a switch which is always operated when thepwheels or discs 9 and 10 occupy a certain angular' position in respect to each other.

The setting of the shaft sections 1 and 2 with respect to each other and of the brush 11 with ,respect to its contact bank having now been described with reference to Figs. 3, 4 and 5, the operation of the switch or selector for semi-automatic or automatic telephone systems shown in Figs. 1 and 2 will now be understood. The selector has al frame comprising two lateral parts 32, 33 with a bottom bent bridge piece 3 and a top bridge piece 31. The lower bridge 31 carries the coupling magnet 4 whose magnetic circuit is formed in the shape of an iron pot or cylinder with a middle core, and the upper bridge carries a journal bracket 44 for theshaft 1. The lower portions of the lateral parts 32, 33 are formed in the shape of broad lugs or ears upon which the magnets 5 and 18 are mounted. The contact bank 36 is connected to the lateral parts 32, 33 of the frame by vmeans of screws 34 and 35. The Contact bank has four rows of bank contacts which are constructed as shown in Figf. The bank'contacts of each row or layer, for example the contacts 33, 26, 30 of each row are embedded in insulation 371, 372, 373, 374. 371 are' of different lengths. Between every two long contacts 30, 33 there is a short or narrow contact 26. The contacts ofthe row.

3 72 are all shaped in the form of straight narrow strips 38. The contacts 39 of the row 373 all extend radially from a common center to a certain distance therefrom where they bend in an oblique direction towards the left. The contacts 4Q of therow 374 also extend radially from a common center to a certain distance where they bend obliquely towards the right. The contacts 33, 26, 3() ofthe row 371l also extendalong a straight line through the insulation 371 to a certain distance beyond the insulation Where they bend towards the left 'when the contactrows yare all in position in the switch. The circle where the j bends of these latter contacts are rotated is within the circle that passes through the bends` of the contacts 39, 40 so that .they form soldering lugs 34 which 4 register with the spaces between the straight parts of the contacts 39, 40.. By this constructionl it is made possible :to interconnect all corresponding cont-acts Of switches mounted vbeside each other by means of straight bare wires as shown in Fig. 7

The construction and generaloperation of the arrangement for setting shafts and of the trates circuits of a connector 300.V In the line linder circuits the starting magnet 15, coupling magnet 4 andthe stepping magnet 18 have the same reference numerals asin Figs. 1 and 3. In the group selector 200 the coupling magnet is designated by 204, the starting magnet by 215 and the stepping magnet bv '218, While in the connector circuits,

9v, 304 indicates the coupling magnet, 315

the starting magnet and 318 the stepping magnet.

The operation of the circuits of the switches will be understood- :trom the following description of theoperations which occur in establishing Va connection through Y the eX- change. It will be assumed that subscriber 101 Wishes to establish a connection with a subscriber 232. .Y

The subscriber 101 raises his receiver from the hook and a current then flows from the positive pole through the line relay 102, contact 103v of the cut-oit relay 104,1Wire 105, sub-station 101, Wire 106, contact 107, of the cut-off relay to the negativerpole. .The line relay is thus energized and at its contact 108 closes a circuit which extends from the positive pole through 108, group relay 109 to the negative pole.' The group relay which is common to a sub-group of subscribers, closes its Acontact 110 and thus sends a starting impulse through the Wire 111 which flows partly through 112, resistance 113, relay contact 114, starting magnet 15 to the negative pole and partly through the coupling magnet 4, relay contact 115, brush 116, bank contact 120, Wire 121, relay contact 122, Wire 123, relay contact 124. to the negative pole. 4'By this means the brushes 116, 117,118, 119 are released by the starting magnet 115 and the cou bling magnet 4, so that the-spring 13, Fig. 3, drives vthe brushesl at, a high speed over the bank contacts. this motion continuing as long as the coupling magnet remains energized. The coupling magnet 4 receives current as long as the brush 116 continues wiping over live contacts like 125, thatis contacts which are con-V nected to the negativ-e pole. As the contact. 126` htnvever, has been disconnected from the negative pole through the opening of the contact 127 of the relay 109 the magnet 4 Will be deenergized when the brush 116 reaches the Contact 126 so that the coupling member 28, Fig. 3, is released by the magnet v4 and the brush 116 is stopped when it reaches the short contact 128 adjacent the contact 126. A Weak current then flows through the coupling member 4 and the changeover relay 129, this current being, suiicient to cause the coupling magnet to attract its armature. This current flows from the positive pole through 110, 111,'contact arm` 130, 112, 4, 115, 116, 128, 121,129 to the negative pole.L y y It is to be noted that` as long as the selector 100 is in its normal position the'relay 129 is short ciruited by a Wire which leads through the relay contacts 124 and 224. This short circuit is, however, opened as soon as the selector 100 is started, because a switch 131 in` the/selector is then closed to complete a Circuit from the positive pole through 131, 132, relay contact 233, right hand Winding of a relay 235. The relay 234 opens its Contact 224 and thus removes the short circuit. that bridges over the relay 129, so that the latter can be energized by a current flowing through the coupling magnet 4 and the contact 128 in the other described manner IVhen the relay 129 is thus energized, it closes its contacts 135, 136, 137 and opens its contacts 129, 115. IVhen the contact 115 is open-ed the coupling magnet 104 which had already been partly deen'ergized so that it was not capable ot keeping its armature attracted, is completely deenergized, By the closure ofthe contact 135 a locking circuit tor the relay 129 is closed through 132 and i 131. At the contact 136 an energizing circuit which is closed later is prepared for the cou- -pling magnet 4, and at contact 137 the circuit of the stepping magnet 18 is closed, this circuit extending from the negative pole through the interrupter 140, 137 and relay contact 141 to the positive pole. Thev stepping magnet 18 now moves theV brushes 116-119 step-by step until the brushes 117, 118, 119 reach the bankcontacts 142, 143, 144. As soon as this happens the stopping relay or test relay 145 is energized by a current Which flows from the positive pole through 110, 130, 1151, 145,

117.v 142, closed contact 146 of the line relay 102, cut-oilV1 relay 104, to the negative pole.

'The relay 145 closes its contacts 147 148, 149, ,150, 151 and opens contact 141, the latter (Vpei'iing the circuit otthe stepping magnet 118. so that the brushes 116 117. 118, 119 stop on the contacts 142. 143. 144. The energization ol thestcpping relay 145 is accompanied h v the cucrgization o't' the cut oit' relay 104. 'this latter opens its contacts 103, 107 and closes its contact 152 so that. after the line rcla \f.102 is deem-rgized. the energizing cur- "rcnt ut relay 145` instead ot' flowing through cont act 146. iowsl through contact' 152 and the relay 104 to the negative pole. The subscriber101 is new connected through brushes 117. 118, contacts 147. 148 and contacts 253, 254 to the impulse relay 255 of the group selector 200.

The impulse relay255 closes its contacts *256, 2561, the contact 250 completing an energizing circuit `for the release relay 258 which extends through the resistance 255). The relay 258 closes a locking current for itself at its contact 260 and at its contact 261 1t closes a circuit for the relay 160 which thereupon closes its contacts 161, 162, 163, 164, 165 and opens the circuit of the starting magnet l5 at contact 114. By its contacts 162, 164, the relay 160 prepares an energizing circuit for the coupling magnet 4 which is closed when the switch 100 is restored on the deencrgization of the release relay 258 in the manner more fully described hereinafter. At its c`ontact 163 the relay 160 prepares a short circuit tor the test relay 145 which is closed through ycontact264 of the release relay 258 as hereinafter described on the initiation of the restoration of the switch 100. At contact 165 thc relay 160 closes a circuit which extends through the contact arm 166 of the trunk tinder TF andthrough the upper winding of the relay 167, whereby the relay 167 is caused to close its armature contacts 168, 169. A current then flows from the negative pole through the interrupter 170, contact 169, driving magnet 171 to the positive pole. The driving magnet now rotates the brushes 166. 130 otl the trunk iinder TF step-by-step until the wiper 160 encounters a conductor for eX- ample 172, which is not connected to the negative pole through the contact of a relay corresponding to the relay 160. At this moment the relay 167 allows its armature to drop back so that the circuit ofthe magnet 171 is opened at contact 169. The wipers 166, 130 of the trunk finder will now stand on a free trunk vso that the line iinder associated with this trunk will be started through the starting wire 111 when the next subscriber calls. The energization of the relay 167 during the travel ofthe Wiper 166 from one bank con- I tact to another is ensured by the lower windgives rise not only to the energization ot" the release relay 258 but also to the energization of the starting magnet 215 of the group selector 200 by a current extending from the negative pole through 256, wire 263, wire 264, 215, to the positive pole. On the calling subscriber 101 now sending in two numerical impulses, two oscillations of the impulse relay armature will be caused thereby and at each detra-ction of this armature a current flows from the negative pole through contact 260, contact 268. 257, wire 269, contact bank connections 270, wiper 275 of the group selector, coupling magnet 204 to the positive pole. At the first impulse through 204 this magnet is caused to attract the coupling member ot the group selector (corresponding to 2 8, Figs. 3,

4 and 5) so that the driving spring (corresponding to 13, Figs. 3 and 4) flings round the wipers to 272, 27 3, 274, 275. As soon as the f wiper 275 leaves the contact 276 the magnet 204 is deenergized, this deenergization taking place even it the impulse through contacts 268, 267 has not ceased, so that the coupling magnet 28, Fig. 3, is jerked up again by its spring and the wipers will thus be stopped as soon as the wiper 275 reaches the contact 277 located between' the two adjacent long bank contacts. At the second oscillation of the armature of the impulse relay 255 another impulse flows through 260, 268, 267, 269, 277, 275 and, through the coupling magnet, this impulse giving rise to another attraction of the coupling member 28 by its magnet, thus allowing the brushes 272, 273, 274, 275 to be flung round onto the contact 278. Vhen the brush 275 reaches the contact 278 the brush carrier is recouplcd by the coupling member 28 to the stationary central shaft of the selec-y tor. Another excitation of the coupling magnet 204 does not take place because in the meantime the impulse relay will have again attracted its armature so as to open the contact 268.

It is to be noted that during the oscillation of the armature of the impulse relay 255 the contact 2561 is opened at each armature oscillation. Consequently the changeover relay 266 receives current impulses that flow from the negative pole through 260` 266` resistance 279, to the positive pole and cause the changeover relay to maintain its armature energized as long as the armature of the impulse relay continues oscillating. Thus contact 257 Ais kept closed andthe contacts 280, 281 are kept open as long as the armature ot the impulse relay oscillates.

When the subscriber has sent in his 1.00 se! lecting impulses for setting the group selector 200 onto the proper bank contact group. the oscillations ot the impulse relay armature cease and the contact 256 is kept closed 'for a comparatively long interval during which it continuously short circuits the changeover relay 266. This relay is thus made to let its armature drop back so as to close at its armature 280 a circuit extending fromY the negative pole through 280, lett hand winding of relay 282 and the ott-normal switch 265, whereby ther-clay 282 is energized and made ,to close its contacts 283, 284, 285. 286 and to open Contact 287. The oit-normal switch 265 is. closed as soon as the two shaft sections of the group selector are moved out of their normal positions relatively to each other and this happensI as soon as the spring 13, which is tensioned b v rotating the shaft section 1, Figs. 3 and 4 relatively to shaft section 2, as hereinbetore described, rotates shaft sect-ion 2. round shaft section 1 in response to the selecting impulses of the calling subscriber.

As soon as the changeover relay 266 is deenergized and the relay 288 is energized in the manner described current impulses flow from the negative lpole through 288, 281, 283, 289, and through the stepping magnet 218 to the'positive pole. By this means the two shaft sections together with the wipers 272, 273,274, 275 are all rotated step-by-step until a free trunk such as 309, Fig. 9, is reached. A current then flows from the negative pole through contact 284 of relay 282, relay contact 290, test relay 291test brush 274, test Contact 292, wire 302, wire 303, contact 304, resistance 305 to the positive pole. The test relay is thus energized .to close its. contacts 293, 294, 295, 296 and open its contacts 253, 254. By the/closure of contact 296 the -relay 234 which was 4deenergized by the opening of contact 233 again received current whichl flows from the positive pole throu' h the'left winding of impulse relay 255, le winding of 234,l contact 296, right hand winding of impulse relay- 255 to the negative pole. By this means the impulse relay 255 iskept energized and alsoV the relay 234 is energized so that it interrupts the circuit of the stepping magnet 218 at contact 289 and closes a locking circuit for itself at its contact 297, said circuit egtending from the negative pole through the right hand winding of 244, 297, oli-normal switch 265 to the positive pole.

The calling subscriber is now connected through contacts 293, 294 to the impulse relay 355 of the connector, this relay being-energized by a current thatiows from the positive pole through the left hand winding of 255, wire 305, bank contact 298, wiper 273, 294, 148, 118, 143, 106, station 101, 105, bank contact 145, wiper '119, 147, 293, 272, 299,306, right hand winding of355 to the negative po e.

The impulse relay 355 closes its contacts 307 308. At contact 307 a circuit'is closed for the release relay 238, this circuit extending fromthe negative pole through armature contact 309, 307, 358, resistance 310 to the positive pole. The relay 358 closes its contacts 311,. 312 and opens its contact 313, 314. By the closure of contact 311 th current path which is independent of the contact 304 is closed through the resist-ance 305, this current path maintaining 'the test relay 391 in the group selector 200 energized when the Contact 304 of the relay-315 is opened in the manner hereinafter described.

Should the calling subscriber, who is now connected through the group selector 200 to the connector 300, now replace his receiver, the impulse relay 355 would -bedeenergized and, due to the de'traction of the armature of the impulse relay, the changeover relay 3,16 wouldbe energized by af-current which, as soon as the contact 308 is opened, flows from the negative pole through 309, contact 312, changeover relay 316, resistance` 317, to the positive pole. The relay 316 then completes at contact 318 a circuit extending from the negative pole through 309, 312, 319, 318, 320, wire 321, wiper 37 5,-;coupling magnet 304 to the positive pole. At the same time a current also flows from the negative pole through 309, 312, 302 to the release magnet 315. By this means the parts of the connector are brought out of their normal positions relatively to each other and the wipers 372, 373, 374, 375 are. rotated by their driving spring until the coupling member, correspondingto 28 of Figs'` 3, 4 and 5, stops the wipers at some intermediate contact, say 378. The shifting of the parts of the connector out of their normal positions results in the closure of vthe off-normal switch 365.` Furthermore by the deenergization of the impulse relay 355 the contact 320 is closed which short circuits the release relay 358 so that it allows its armature to drop back, whereby the contact312 is opened and contact 321 is closed, so that a current flows from the negative pole` through 309, 321, left hand winding of relay 315, off-normal switch 365 to the positive pole. The rela 315 is energized to open its contact 304. gince Contact 311 is also opened the current liowing from the positive pole through 305, 302, bank contact 292l through the test relay 291 is now interrupted so that the test relay-291 allows its armature to drop back so as to deenergize the impulse relay 250 by opening contact 296. By this means the restoration of the group selector 200 toits normal position is initiated, the release relay being short circuited at contact 257 and thus caused to close its Contact 233'. Current impulses then ow from the negative pole through 288, 233, armature contact IUI:

`285, and thestopping magnet 218. At thei same time lthe coupling magnet 240 is energized by a currentiowingrfrom the negative pole through the contact 265 of the release relay, contact 27 0 of relay 278', arma- .ture contact 286, 204 to theA positiveY pole.

The two shaft sections of the group selector are thereby uncoupled Yfrom each l,other so that the current impulses flowing through the 'stepping magnet 218 rotate'the shaft section 1 (Figs. 3 and 4), While the shaft section 2 is held stationary by the armature ofy the starting magnet 215. The shaft section 1 is now rotated jb 1 the stepping'magnet 218 and the spring of t e group selector is thus wound up until the two shaft sections have been turned into their normal positions relatively to each other andthe off-normal switch 265 isfopened, whereby the relay 282I is deenergized,l The relay`282 then 'opens its arina.

ture contact 286 so as to again deenergize the` coupling magnetc204, and recouple the shaft sections 1 and 2 to each other. The

stepping magnet 218 now receives further imtime the starting magnet 215 is energized by a current flowing from the negative pole through armature contact287, Contact 268 of switch 280', 215 to the negative pole. The intercoupled shaft sections together With the brushes 272, 273, 274, 275 are now rotated further until'they reach their normal position at the commencement of the contact bank and the oit-normal switch 280 is opened so as to interrupt the circuit of the stepping magnet 218 and the circuit of the starting magnet 215. v They parts of the selector 200 will now be in their normal position.

It is to be noted thatduring the Winding` up of the spring of the group selector that is during the step-by-step rotation of the shat't section 1 by the stepping magnet 218 and the simultaneous excitation of the coupling magnet 204 and deenergization of the starting magnet 215, the coupling magnet 204 after its initial 4energization is energized by current flowing through the contact 270 and resistance 250 so that the pull exerted` of the armature 27 (Fig. 4) is weakened and only a comparatively small pressure of the shaft 1 on its lower journal 7 takes place. The insertion of the vresistance 250 inthe circuit of the coupling magnet is eiiectedbythe relay 27 8 which opens the contacts 270 slow- -ly When it is excited current flowing from the negative polethrough a contact 265', 27 8',y sWitclr-265'to'the positive pole.

Thedeenergization of the release relay 258 also results in the rewinding of the spring of the line finder 100. When the release relay 258 is deenergized the relay 145 is short circuited by the closure of the contact 264, which results in the closure of a short circuit extending through 240, 163, armature contact 149 of the test relay.' The armature of the test relay is thus caused to drop back slowly. Before the armature of the relay 145 executes itsbackward travel, the coupling magnet 4 is `energized by a rcurrent flowing from the negative pole through 263, 164, 136, 4, 4151, 162, to the positive pole. The coupling mag-- net 4 attracts the coupling member of the line finder and thus uncouples the twoshaft sections 1 and 2. As soon as the armature of the release relay 145 drops back the Contact 151 is closed and the armature ot the coupling magnet- 4 is then kept attracted by a comparatively Weak current flowing through the resistance 113. The detraction of the armature of the relay 145 also results in the closure ot a circuit through the stepping magnet 18 of the line inder, extending from the positive pole through 141, 137, 18, 114, to the negative pole. The armature ci the starting 'magnet 15 maintains the shaft section 2 stationary whilst the stepping magnet 18 turns the. sha-ft section 1 and thus Winds up the spring 13 (Figs 3 and 4; of the line finder, this ie'winding operation continuing until the switch 131 is opened when the spring will be fully retensioned and at the same time the relays 1GO and 129 Will be deenergized. As soon Vas the relay 129 is deenergized, the circuitof the stepping magnet 18 is opened at the armature Contact 137. The spring of the line finder having new been fully rewound, the line tinder will be ready for renewed use. T he connector which was brought out of its normal position is also restored in the following manner: On the contacts 293` 294, being opened at the deenergization oi' the test relay 291, the impulse relay is also deenergized and the release relay 358 short circuited through contact 320. The relay 358 closes at its Contact 321 and enerizing circuit for relay 315 extending from the negative pole through 301, 321.1relay 315. switch 365 to the positive pole. The relay 3151 closes at contact a locking circuit for itself extending from the negative pole through its right hand Winding, oli-normal switch 365 -to the positive pole. The relay 3151 at-its Contact 323 also closes a circuit for the ,stepping magnet 318 (positive pole, 318, 323, 313, interrupter 324, negative pole) and at contact it closes a circuit for the coupling magnet` 304 extending trom the negative pole through contact 314, 327, 304 to the positive pole. In the energizing circuit of the coupling magnet 304 a resistance 323 is inserted after a brietl interval by the opening ot the contact 327 by means Aot' relay 326 which, immediately after the initial energization of the coupling magnet 304, is also energized by a current flow-M ing from the negative pole through 325, 314, 326, 329 to the positive pole. Whilst the coupling-magnet 304 is thus energized by a comparatively Weak current which is only just strong enough to keep the coupling mem. ber attracted and While at the same time the starting magnet 315 is deenergized', the stepping magnet receives current impulses rby which the shaft lsection 1 of the connector is rotated step-by-step until the switch 365 is opened and the relay 3151 is thereby deer;- crgized. l/lhen thc relay 51 is deenergized the couplinginagnct 304 and the relay 323 are also deenergized by the opening of contact 325. At the same time, the closure of the Contact 313 of the deenergized relay 3151 results in tha-eener?,ization of the starting magnet 315, iyhile the magnet 318 receivescurrent impulses through contact 331 of switch 332 which flow from Athe negative pole through the interrupter 324, 313, 333, 331,731 to the positive pole. The shaft sections 1 and 2 gether on account ot e deenergiaation ot the cou magnet two shaftsections toget -er with the brushes 2, 373, "7 375 are rotated together step-by-step until the switch 332 is opened upon the brushes 372 to 375 reaching their normal position when the circuit oi' the stepping magnet 318 is opened at Contact `331 and the circuit of tl e of the connector beine cou aled tostarting magnet 315 is interrupted at contact 334. rlhe various parts which were taken into use as a result of the partially established c'onnectlion have 110W been returned to their normal positions.

It will noW be assumed that the .callfng subscriber, Whose connection has been extended tothe connector, Fig. 9, proceeds With the establishment of the same and sends in a series of tens impulses whichv e'ect the impulse relay 355 at each tens impulse, a current Hows from the negative pole through 309, 312, 319, 3181 of the changeover relay 316 which is kept energized during the oscillations of the impulse relay of 355, contact 320 of the relay 315 which 1s not yet energized, Wire 321, contact 3741, Wiper 375, coupling magnet 304, to the negative pole. In response to the first tens impulse the spring 313 (Fig. 3) jerks the brushes 272-275 up to the bank contact 335. In response to the second and third tens impulses the said spring turns the Wipers rst to bank contact 336 and then to bank contact 337. The impulse relay 355 is maintained energized for a comparatively long interval between the tens and units series of impulses, and during this period the changeover relay 316 is short circuited by 4 contact 308 so that it opens its contacts 3181,

338 and closes its contacts 339, 340. On the closure' of contact 339 the relay 3151 is encrgized by a current which flows from the negative pole through 309, 312, 339, left hand winding of relay 3151 to the positive pole. The relay 3151 is energized to open its contacts 320, 330, 3041 and close its contacts 3411, 342, 322, 323 and 325. The calling subscriber now sends in the units impulses, the number of Which in the present instance is 2, 4thus giving rise to tWo deenergizations ot the impulse relay The moment the relay 355 is deenergizcd in response to the {irst impulse the short circuit 'ot the changeover relay 316 is removed at Contact 308 so that the changeover relay again attracts its armature. At each units impulse a current flows through the stepping magnet 318, its circuit Vextending from the negative pole through 309, 312,

sie, 3181. 342, als to the positive pole. The

shaft sections 1 and 2 which are coupled together and hence the Wipers 372-375 are thus rotated two steps so as to cause the Wipers 372-375 to land on the bank contact set 332. The units impulses having new ceased the changeover relay 316 is again kept short circuited at contact 308 and thus caused to let its armature drop back. It is thus to be noted that on the deenergization of theV changeover relay 316, when the first units impulse was. sent in, the relay 343 was energized by a current flowing ,from the negative pole through 309, 312, 338, 341, lett hand vviudiintf ci' relay 343 to 'th`e positive pole. The relay 343 closed its contacts 344, 345, 346. Through contact 346 a locking circuit is established for the relay 343 including its right hand Winding and the contacts 312,309.

0n the changeover relay 316 bein again short circuite'd through contacts 308 agiter the units impulses have been sent in the deenergization of the same results in the negative pole of the battery being connected through contacts`309, 312, 339, 345 to the test relay 347. It' the test brush 374 is in contact With a free test Wire, that is to a wire upon which there is a certain positive potential, the test relay 347 Will be energized to close its contacts 348, 349, 350, 351 and open its contact 352. By the closure of contact 348 the ringing relay 326 is caused to be periodically energized bycurrent through an interrupter that sends impulses from the negative pole through 348, 326, contact 329 to the positive pole. At each energ'zation of the relay 326 the ringing current generator 354 is connected through contacts 353, 355 to the called line so that the bell of the one subscriber rings. When the Wanted subscriber responds by raising its receiver from the hook of his instruments the ringing cut-oil and battery feed relay 356 is energized by a current tlowin from -the negative pole through the le t hand Winding of 356, contact 357, 349, Wiper 372, one wire of the talking circuit 232 to the call station, back through the other Wire to the exchange, thence through 373, 350, 358, right hand Winding of 356 to -the positive pole. By the energzation of relay 356 the ringing relay 326 is disconnected at contact 329. At the same time the relay 362- is energized by a current flowing from the negative pole through contact 361, left hand Winding of 362, switch 365, to the positive pole. r1`he relay 362 opens its contact 309 but only after the negative pole is connected through 360 to the Wire 363 and thus to the contact 312 to maintain the energization of the release relay 358. The relay 362 closes Iat its contact 364 a locking circuit for itself extending from the positive pole through 365, right hand Winding of 362, contact 364, 312, 360 to the negative pole. The calling and called subscriber can now converse through the Wires drawn in Figs. .8V and 9 with heavy lines. i

-If the called subscriber is rst to replace his receiver at the end ot the conversation the circuit of the release relay 358 will be interrupted at contact 360 yon the deenergization of the relay 356.A The release relay 358 then closes at contact313 an impulse circuit extending through 331 of switch 332 and the stepping magnet 318. At the same time the'coupling magnet is energized by a current Howing from the negative pole, through 325, 314, 327, 304 to the positive pole. immediately after the energization vof the coupling magnet 304 by the current flowin through `cont-act 327 this Contact is opened y the energization of the` relay 326 which is eective ESG stepping impulses during the flowing of which the coulping magnet 304 is energized by a weak current just suiiicient to maintain its armature attracted whilst the starting f magnet 315 is deenergized. As soon as the shaft section 1 is restored to its normal position with respect to shaft section 2 the olinormal switch 365 is opened whereby the relay 315 is energized in addition to relay `362 so that now the starting magnet 315,

which was deenergized by the opening of the contacts 360, 312, is again energized by a current iiowing from the negative? pole through 330, 334, 315 to the positive pole. The impulses which iiow through the stepping magnet 318 now cause the two intercoupled shaft sections 1 and 2 together with the wipers 37 2-375 to rotate step-by-step until the wipers reach their normal position in which they are shown in Fig. 9. At this moment the oft-normal switch 332 is .opened whereby the stepping magnet 318 is switched off at Contact 331 while the starting magnet 315 is switched off at contact 334. The various parts of the connector have now been re` stored to their normal positions.

If the callingsubscriber replaces his receiver iirst the deenergization of the release relay 358 is effected by the short circuiting of the same through contact 320. By this means the restoring operations are initiated to take place in the manner already described so that they need not be repeated.

It will now be assumed that at the moment the negative potential is applied to the test relay 347 in the manner already described the called subscriber is engaged. The test relay 347 will thennot' be` energized and a busy tonecurrent wilt be sent from the busy tone producer 390 through the coil 391 which is wound on the impulse relay 355. The busy tone current flows from the busy tone producer 390 through contact 340, 344, 352, 391 and back to 390. A secondary busy tone current is then induced in the coils of relay 355 and thus sent to the caliing subscribers station, apprising him of the fact that thewanted line is busy so that he will replace hisv receiver and the relay 355 will he deenergized and initiate the restoring operations already described.

In Figs 10 and 11 circuitsv are shown by 'which the speed at which the wipers are driven up to a desired group of bank contacts may be increased at' will and by which the number of steps or extent of travel that the wipers have to execute, after they have reached the desired bank Contact group may be reduced to any desired extent. In Fig. 10 the magnet 41 corresponds to the coupling magnet 4, Fig. 8, and 1161 corresponds to brush 114, Fig. 8. 1091, 1092, etc. correspond to the subgroup relay 109 ot Fig. 8. It the wiper 106 of the started switch is to be stopped at the beginning of the fourth group of contacts that is at Contact 401 the negative pole, which is ordinarily connected to all long contacts or group contacts, is disconnected from the three group marking contacts 402, 403, 404 located before the group marking contact 400, this being effected by the subgroup relay 1091. It is obvious that when the wiper 1161 travels over the contacts 402, 403, 404 the current owing' through the coupling magnet 41 stops ilowing as soon as the wiper commences travelling over contact 402 and this cessation of the current continues whilst the wiper travels over 403, 404. The duration of cessation'ot the rlow ot current through the coupling magnet 41 is theretore the time that the wiper 1161 requires to travel over the three contacts 402, 403, 404. The Wiper 1161 may therefore be moved over the group marking contacts three times as that as it only one group marking Contact like 402 were disconnected from the negative ole. p It the arrangement of the coupling is such that the coupling magnet is to couple the shaft sections when it is energized (instead ot deenergized as in 1dig. 10) the circuits are modified as -shown in Fig. 11 in which 109", 109', 1092, etc. denote the subgroup relays, 42 the coupling magnet and 1162 the wiper connected to the coupling magnet. It a subgroup relay say 109d attracts its armature the negative pole is connected to the group marking cont-acts 4021, 4031, 4041 and the coupling magnet 42 receives current when the brush commences travelling over the i'irst ot these three contacts. The brushes are brought'to astandstill when they reach the contact 40401, it being assumed that the time that the magnet 42 requires to attract its armature is equal lil-6 to the duration of travel ot the brush 1162 is over the three contacts 4021, 4031, 4041. g

In this manner the speed at which the wipers are driven of to the the'bank contacts may be made three as great asi .the potential were taken (Fig. 10) or applied (Fig. 11) freiner to only one of the group marking contacts situated before the desired Contact group. By arranging the circuits so that a single subgroup relay effects a still greater number ogroun mar ing contacts the speed of travel of brushk 116 may be increased to a stili greater proper group of extent. Conversely the number of contact sets in a subgroup may ne decreased ko that after the wiper has reached the desired convthe disk 610 as `illustrated in Fig. 15.

tact group a number of steps or the extent ot' 1ts travel is decreasedsayfrom teny steps (or a corresponding distance) to three steps orv even one step.

Figs. 12 to 15 show a modied switch in which only two magnets instead of three are employed. Besides, the contact bank which lis not shown in Fig. 12 has a different arrangement of vits soldering tabs, this arrangement being shown in Figs. 16 and 17.

In Fig. 12 604C is the coupling magnet and 618 the stepping magnet which corresponds to the magnets 4 and 18 of Fig. 1, the third magnet being omitted. The disk 610 attachedto the brush carrier is shaped as shown has an oblique bottom surface 614 rides up "-onto the disk 610 and slides on its outer ring- 'v615. ln the operation of theswitch the disk [10 Xed to the brush carrier will be stopped 5.30. y

sto ped at the beginning of the desired group the coupling member 631 rising ontoone of the openings 611 when the brushes will be o ank contact sets of the line finder, group selector or connector as the case may When the switch is restoredvthe coupling Ymember 631is pulled out of the opening again n and the Adisk'610 then rotates -further until the opening 612 reaches the movable Istop 61.3. l This stop then drops intoV the opening 612 and when the leg 616 reaches the stop 613 the disk 610 will be stopped. The'spring of the switch is then rewound, or-the normal relationship between the rotary shaft on which the hollow shaft or brush carrier is journalled, is then restored b the stepping wheel 629 being stepped round y the stepping pawl 'until' the member 631- reachesv the opening 612, la switch consisting of the springs 635,

636 is opened to deenergize the magnet e andat the moment the coupling member 631 registers with the opening 612,- another switch consisting of the springs 636, 637 is` opened to deenergize the stepping magnet 618. The coupling member 631 ,thus enters the opening 612 and lifts the stop 613to its normal position. The switches consisting of the springs 635, ,636, are .actuated by a cam 638 with cam .surfaces 639, 1640-., The cam 638 is'ixed to the stepping wheel Shortly beoretie coupling member 631 reaches its normatlposition, that is to say shortly befpre it .registers with the opening 612. the sprlng 663. rides up onto the cam surface 639. When .the coupling member 631 registers with the opening 612 the spring'641 rides up onto the surface640. By this-means the switches 635, 636 and 636, 637 are opened in succession.

` In the operation of setting the brushes of the switch onto the desired group of bank contacts the coupling member 631 is con trolled in a line finder in a manner already described in connection with the switch 100, Fig. 8;4 When the modifiedswitch is used as a connector the long group designating contacts and the short contacts between them which are used in the switch 200 are replaced by an interrupter consisting of springs 650, 651 and eifected by the projections 652, 652', 652" etc. 01"' the disk or spider 610. The group selecting impulses are sent through the springs'650, 651 into the coupling magnet 604, each group selecting impulse causing the j coupling magnet 631 to be drawn out of engagement with the spider 610. When the spider is moved by its propelling agent or spring the interrupter 650, 651 is opened through the spring 660 entering a recess such as 655 between 2 projections 652. At each new current impulse the spring 660 willhave ridden up onto a new projection 652. 1t is thus seen that the projection 652 corresponds in a sense to the short contacts like 276, 277, switch 200, Fig. 8, and the recesses 655 correspond to the long dead contacts bet-Ween the short contacts, switch 200 Fig. 8. The pawl 630 normally engages with a tooth of the wheel 629. Since the pawl strikes against a stop 670 the wheel 629 is normally pre- .vented from rotating in the direction at which'it is stepped when the pawl 630 is operated by the armature 671 oi the magnet 618. The pawl 630 is connected to the armaico `ture 671 by a lever or arm 672. The rear end of the arm terminates in a member"67 3 bent at right angles through the arm 672 and attached to the' armature 671 by screws v6711*, 675. The member 673 has oblong holes so that the arm 672 can be adjusted in the directions indicated by the arrow 676. By thus bank Contact may thus be altered at will, .f

i. e; the point at which the brushes touch a contact when the pawl 630 is in engagement with the wheel 629 ,as shown may ,be advanced or displaced rearwardly at will rthis adjustment orcorrectionot1 the brush position on a bank contact can be eiected without altering the gap or stroke between the armature and the pawl faces of the stepping magnet. The arm 672 with its pawl 630 are urged in the direction of the arrow 67by the spring 678 whose tension may-beV adjusted by the'screw latch 680.

du the foregoing description mention has been made of the pressure exerted by the end vadjusting the arm 672 andk by also shifting of the central shaft on its end bearing when the coupling magnet is energized. This pressure can be minimized as hereinbefore described by cutting a resistance into the coapling magnet circuit when it has attracted its armature. To eliminate this pressure and the resultant friction altogether the coupling magnet, instead of being fixed to the switch frame, may be mounted on the central switch or attached to the stepping wheel so as to rotate therewith,

To enable the banks of several switches mounted-side by sideto be interconnected in a simple manner by bare wires, the bank con'- tacts are provided with tabs o f the kind illustrated in Figs. 16 and 17. In Fig. 16, 670 is the top contact of a set of three bank contacts. The contact 670 has a soldering tab in the form of a projection 671. The contact beneath the bank contact 670 has a soldering tab 672 which is shorter than 671. The third contact corresponding to 67 Q has a tab in the form of a still shorter projection 637 protruding from the contact bank mounting 674. Ity will be noted that the tabs 672, 673 project beyond the lateral edge of the narrow part of the tab 671. The corresponding set of bank contacts 671", 672. 67 3, Fig. v17 in a switch mounted beside the switch shown in Fig. 16 can therefore be multiply connected by vbare wires 674, 675, 676 stretched straight from one soldering tab to another such as the wire 674 stretched from the tab 671 to 671. It will be apparent that a bank contact set may consist of practically any number of bank contacts without any dificulty in the interconnection of adjacent corresponding sets of bank contacts by bare wires or wire ribbons arising.

I claim 1. In a circuit switching' mechanism, two coaxial shaftmembers adapted to be rotated in one and the same direction, an electromagnetically operated stepping pawl for holding one of said members against rotation,

an electromagnet having an armature, and means controlled by the armature ofv said electromagnet for normally holding the other member against rotation.

2. In an electric circuit switching mechanism, a shaft, a stepping wheel fastened to said shaft, a stepping pawl normally holding said wheel against rotation, a hollow shaft journaled upon said first-mentioned shaft, an electromagnet having an armature, and means controlled by said armature for holding said hollow 'shaft against rotation.

3. In an electric circuit switching mechanism, a shaft, a stepping wheel attached to said shaft, an electromagnetically operated stepping pawl normally holding said wheel against rotation, a hollow shaft journaled upon said shaft, an electromagnet having an armature, means controlled by said'armature for holding said hollow shaft against rotation, and a coupling member carried by one of said shafts when either shaft is rotated. v

4. 'In an electric circuit switching mechannism,a shaft, a stepping wheel attached to said shaft, al stepping pawl for normally holding said wheel against rotation, a hollow shaft, journaled against said first-mentioned shaft, a spider carried by said hollow shaft, an electromagnet having an armature engaging said spider to hold the hollow shaft against rotation, and a'coupling member carried by said first-mentioned shaft and cooperating with said spider.

5. In an electric circuit switching mechanism for automatic telephone systems, .1, retatable brush adapted to execute sepa ate group and terminal selecting movements, two coaxial shafts, one arranged within the other, a wheel attached to each shaft, one of said wheelsadapted t-'o control the group selecting movement and the other of said wheels adapted to control the terminal selecting movement of said brush, and a` coupling member pivoted to one of said wheels havingv its free end in cooperative relation with the other of said wheels.

6. In an electric circuitswitching mechanism for automatic telephone systems, a brush adapted to execute separate group and terminal selecting movements, two shafts, one adapted to control the group selecting movement and the other the terminal selecting movement of said brush, means for turning said shafts in the same direction, a notched disc mounted on one of said shafts, an electromagnet having .nan armature and a pivotal mounting` for said armature on the other one of said shafts so that its free end cooperates with said notched member.

7. In an electric circuit switching mechanism for lautomatic telephone systems, a brush adapted to execute separate group and terminal selecting movements, two shafts, one for controlling the group selecting movement of said brush and the other for controlling the terminal selecting movement of said brush, a notched member affixed to one of said shafts, an electromagnct, an armature forsaid magnet having a tongue cooperating with said notched member and a pivotal mounting for said armature on the other of said shafts.

8. In an electric circuit switching mechanism, two shaft members, a contact bank having sets of contacts arranged in parallel rows, wipers carried by one of said shaft members cooperating with said bank, means for rotating said shafts in the same direction, and a spiral spring interconnecting said members wound up during the rotation of one of said shaft members.

9. In an electric circuit controlling switch, a contact bank having sets of contactsarranged in parallel rows, a wiper, means 'for operating said wiper to cooperate with said isa A movement of said member for actuating said detcnt, and an electromagnet for operating said detent depending on the position of said member.

11. In an electric circuit controlling switch, a wiper, a carrying member therefor, a spring adapted to cause the rot-ation of said member, a detent for said member actuated in response to a certain movement of said member, an

electromagnet for operating` said detent, and mea-ns depending on the movement of said wiper for actuating said magnet'.

12. In a: circuit switching mechanism, two coaxial shaft members adapted to be rotated in one and the same direction, an electromagnctically operated stepping pawl :forholding Yone of said members against rota-tion, an electromagnet having'v an armature, means controlled by the armature of said electromagnet for normally. holding the other member against rotation, an electric circuit'for energizing said electromagnet, and a remotely controlled relay armature for controlling said electric circuit.

13. In an electric circuit su'itchi'ng mechanism, a shaft, astepping wheel fastened to said shaft, a stepping pawl normally holding said wheel against rotation, a hollow shaft journaled upon said first-mentioned shaft, an electromagnet having an armature, means controlled by said armature for holding said hollow shaft against rotation, an electric circuit for energizing said electromagnet and a remotely controlled relay armature for controlling said electric circuit.

14. In an electric circuit switching mochanisx'n, a shaft, a stepping wheel attached to said shaft, an electromagnetically operated stepping pawl normally holding said wheel against rotation, a hollow shaft -journaled upon said shaft, an electromagnethaving an armature, means controlled by said armature for holding said hollow shaft against rota.-

'tion, a coupling member carried by one of said shafts when either shaft is rotated, an electric circ-uit for energizing said electromagnet, and

. a remotely controlled relay armature for controlling said electric circuit.

1 5. In an electric circuit switching mechanism, a shaft, a stepping wheel attached to said shaft, a stepping pawl for normally holding said wheel against rotation, a hollow shaft 'journale'd against saidv first-mentioned shaft, a spider carried by said hollow shaft, an electromagnet having an armature engaging said spider to hold the' hollow shaft against rotation, a coupling member carried by said first-mentioned shaft and cooperating with said spider, an electric circuit for ener-- gizing said electromagnet', and a remotely controlled relay armature for controlling said electric circuit.

16. In an electric circuit' switching mechanism, two shaft members, a contact bank, wipers carried b-y one of said shaft members cooperating with said bank, means for rotating said shafts in the same direction, a spiral spring interconnecting said members wound upv during the rotation ofone of said shaft members, an electric circuit for energizing said eleqtromagnet, and a remotely controlled relay armature for controlling said electric circuit.

17. In an electric circuit controlling switch, a contact bank, a wiper, means foroperating said wiper to cooperate with lsaid contactbank, a stopping magnet for said wiper, means for supplying current to said stopping magnet depending on the speed at which the wiper is moved andthe number of bank contaets traversed thereby, an electric circuit for energizing said electromagnet, and a remotely controlled relay armature for controlling said electric circuit.V

18. In an electric circuit controlling switch, a wiper, a wiper-carrying member, means for applying driving force to said member, a detent forsaid member, means responsive to the movement of saidmember .for actuating said detent, an electromagnet for operating said detent depending on the position of said member, an electric circuit for energizing said electromagnet, and a remotely cont-rolled relay armature for controlling said electric circuit.

19. In an electric circuit controlling switch, a wiper, a carrying member therefor, a spring adapted to cause the rotation of said member, a detent for said member actuated in response to a certain movement of said member, an electromagnet for operating said detent, means depending on the movement of said wiper for actuating said magnet, an electric circuit for ene rgizing said electromagnet, and a remotely controlled relay armature for controlling said electric circuit.

20. In a circuit switching mechanism, two coaxial shaft members adapted to be rotated in one and the same direction, an electromagnetically operated stepping'pa-wl for holdingone of said members against rotation, an electromagnet having an armature, means controlled by the armature of said electromagnet for normally holding the other member against rotation, and a remotely controlled oscillatory relay armature for sending current impulses through said electromagnet.

21. In an electric circuit switching mechanism, `two shaft members, a contact bank, wipers carried by one of said shaft members cooperating with said bank, means for rotatlll lib

tacts traversed thereby,

-applying driven force ing said shafts in the same direction, a spiral spring interconnecting said members Wound up during the rotation ofone of said shaft members, and a remotely controlled oscillatory relay armaturefor sending current impulses through said electromagnet.

22. In an electric circuit controlling switch,

va contact bank, a Wiper,means for operating `sald wlper to cooperate Wlth sald contact bank, a stopping magnet for said Wiper,

vmeans for supplying current to said stopping magnet depending on the speed at which the Wiper is moved and the number ofvbank conand a remotely con` trolled oscillatory relay armature for sending current impulses through said elec-tromagnet.

23. Inan electric circuit controlling switch, a wiper, a Wiper-carrying member, means for to said member, a detent for said member, means responsive to the movement of said member for actuating said detent, an electroma net for operating said detent depending on ie position of said member, and a remotely controlled oscillatory relay armature for sending current impulses through said electromagnet.

24. In an electric circuit controlling switch, a Wiper, a carrying member therefor, a spring adapted to cause the rotation of said member, a detent for said member actuated in response t0 a certain movement of said member, an electromagnet for operating said detent, depending on the movement of said Wiper for actuating said magnet and a remotely controlled oscillatory relay armature for sending, current impulses through said electromagnet.`

In testimony whereof I afiix my signature.

FRITZ ALDENDORFF. 

